What Do Zebrafish Have To Do With Curing Blindness?

September 22nd, 2016 by FFB Canada

According to Dr. Sarah McFarlane, zebrafish hold important clues to restoring sight. These tiny, transparent, iridescent creatures provide Dr. McFarlane with a window into eye development, eye disease, and ultimately, to new treatments.

In the blinding eye disease age-related macular degeneration (AMD), vision loss occurs when cells in the eye begin to die. This process of degeneration involves two different kinds of cells: 1) retinal pigmented epithelial (RPE) cells and 2) photoreceptor cells. In the healthy eye, the RPE cells provide critical support to the photoreceptors, which are the eye’s light-sensing cells. In AMD, these RPE cells begin to degenerate. After the RPE cells are damaged, they can no longer provide support to the photoreceptors, which then begin to die too and vision loss progresses.

Currently, stem cell replacement therapies for AMD are testing if healthy RPE cells (made from stem cells) can replace damaged RPE cells. To be successful, these transplanted RPE cells need to find their way to the exact sites of RPE damage. This is where Dr. McFarlane’s zebrafish enter the story. By studying zebrafish, Dr. McFarlane is able to identify key molecules that promote and direct the movements of RPE cells. She hopes that this information will help to ensure the development of an effective cell replacement therapy for AMD.

To learn more about how different cells in the eye behave and interact, Dr. McFarlane has designed a new method to track cell movement in real-time. One of her experiments involves labeling cells with different colours (green or red) and then tracking their movements over time, which reveals how and when they move. “This year, we made progress on this experiment by finding out a way to label only these cells in the live zebrafish.” She explains that “this new finding brings us closer to new treatments because we now have the tools to understand the normal behaviour of these RPE cells, which are so important for photoreceptor function, which, in turn, allows us to better understand what goes wrong with these cells in retinal disease.”

Recently, Dr. McFarlane opened her lab to members of the FFB community. She answered questions about her research and explained what it means for people living with blinding eye diseases. Dr. McFarlane describes her work as “basic” or “discovery” science research. This means that she is trying to understand fundamental biological processes; in her case, how the cells of the retina are formed, move and function. She explains “we need this basic information to understand what goes wrong in disease, and to identify the best strategies for treatments in order to correct the defects.”

At the same time, she realizes how vital treatments are to patients who are living with progressive vision loss or blindness. “From a scientist’s point of view,” explains Dr. McFarlane, “forging ahead with treatments without key understanding of how these cells work might lead to failed treatments.” Because of this, Dr. McFarlane emphasizes the importance of funding all levels of the research continuum – from basic science, like her work on zebrafish, right through to clinical trials.